2007 4dr EX - Driver door lock - Help diagnose
 

Hello everyone and thanks in advance for the help. My 2007 Honda Accord, at 140,000 miles, is having some performance issues in the door locking and unlocking category. Please help me determine what I need to repair/replace and if I can handle it without taking it to a professional. Symptoms:

1. The car does not unlock any door from the key fob. I do see the lights flash and hear the sound of a halfhearted attempt from the actuators. The driver's door lock twitches but does not travel. No doors unlock after multiple presses of the fob to unlock.
2. The car is accessible after using the manual key position on the driver door handle. The driver door lock unlocks as designed.
3. Once inside, all doors except the driver door can be locked and unlocked by use of the switch on the driver door. Additionally, by pushing the driver's lock stock down, all others go down. No movement from the driver lock from the interior door switch.
4. Starting with all doors unlocked and walking out of the car, none of the locks go down by use of the key fob.
5. If I am driving away unlocked, the doors are not automatically locking at any speed tested up to 65mph. (honestly can't remember if they ever did this)
6. When leaving the car, I can lock all doors by manually pushing the driver lock stock down. All door locks follow the locked position.

Do I need to replace the driver actuator or am I missing something? Where should I get the part? And am I safe to continue using the fob until it is replaced? Will I still be able to use the key fob remote once replaced?

Thanks for your help!

I'd change the battery on the key fob just to be thorough.

Does the fob work to unlock and pop open the trunk?

How do the locks behave when using the passenger door lock/unlock switch ?

I'll give changing the fob battery and using the passenger door a shot tomorrow.
The fob does work to unlock and pop the trunk.

Your description of the issues doesn't point to one component in the system.

The fob works by sending a signal to the fob antenna built into the driver's door switch. All driver door inputs (fob, key, lock/unlock switch) are sent from the driver's door switch digitally through a network wire to the MICU (multiplex integrated control unit in the driver's fuse box). The MICU powers the lock actuators depending on the input. The passenger and other door inputs are sent direct connections to the MICU.

Since the passenger and rear doors lock/unlock the MICU is able to send enough power to the actuators if it gets the correct signal.

I like to test as much as possible before replacing a part. You could have a bad driver's door switch. The wiring from the driver's door that goes through the rubber boot into the body can have some damage. The wiring can have issues due to wires bending when opening/closing the door, or somehow you are not getting enough voltage to the driver's door switch. The MICU is also a possibility as well.

We can give you some tests that would require a test light or a volt meter to avoid replacing a properly working part, where you would check for good power and grounds at the driver's door switch and pull the driver's panel to test at the actuator connector. It depends on how much you want to test before replacing a part.

Went out and did some extra testing this morning based on these responses. I replaced the battery in my typical remote and used the spare: same results.

• When using the remote to unlock the car: The lights flash and the red flashing lock light on the dash clears, indicating the signal to unlock is received and the alarm is cleared. No locks unlock. No sounds are made from any lock or door.
• When using the remote to lock the car: Audible sound heard from all doors in an attempt to lock (but were already locked). I forgot to try this from an unlocked state... I'll give it a shot later this afternoon from unlocked.
• From the passenger door handle switch: Unlock switch unlocks all but the drivers door. Lock switch locks all but the driver door. This is the same response as the driver door switch.

For testing: I am happy to do some testing with a DMM, but I don't have a test light or adapters outside the standard DMM prongs. Certainly don't want to damage any cable housings/fittings.

Thanks for the continued support!